Remote switch control apparatus



Jan. 2, 1968 w. TLBURR REMOTE SWITCH CONTROL APPARATUS Filed July 15, 1965 2 SheetS- -Sheet 1 Kbrk- Jan. 2, 1968 w. T. BURR 3,360,936

REMOTE SWITCH CONTROL APPARATUS Filed July 15, 1965 2 Sheets-Sheet 2 Fig .2.

' v HQ United States Patent Ofi Fice 3,360,936 Patented Jan. 2, 1968 3,360,936 REMOTE SWITCH CONTROL APPARATUS William T. Burr, Shoreham-by-Sea, England, assignor to Fine-Blanking Limited, Shoreham-by-Sea, England Filed July 15, 1965, Ser. No. 472,280

' 7 Claims. (Cl. 60-54.5)

ABSTRACT OF THE DISCLOSURE A hydraulic press in which the switches for initiating the various operations of the press are arranged remote from the ram'of the press by having a master cylinder containing a' piston connected to the ram and a slave cylinder connected to the master. cylinder and containing a piston connected to a cam bar carrying cams for operatingv the switches. x

The present invention relates to remote switch control apparatus and more particularly to such apparatus for the remote control of microswitches on a hydraulic press.

According to the present invention there is provided remote switch control apparatus for a press or other device comprising first cylinder means operated by means of the device which first cylinder means causes fluid pressure to operate second cylinder means which are operatively connected to a switch operating device.

Further according to the invention further means are provided for maintaining a minimum fluid pressure on said first and second cylinder means and for ensuring that the switch operating device does not operate by means of the minimum pressure.

A constructional form of the invention will now be described by way of example with reference to the accompanying drawing wherein:

FIGURE 1 shows a remote switch control apparatus made in accordance with the invention; and

FIGURE 2 shows a modification to be described.

The remote switch control apparatus comprises a first or master cylinder 1 having a plunger 2 which is connected to and moved by the ram of a hydraulic press, the plunger 2 when moved in one direction causing oil in the cylinder 1 to be forced along a pipe 3 to the cylinder of a second or slave cylinder 4 having a plunger 5, the pressure which builds up causing the plunger 5 of the second cylinder 4 to move, this plunger 5 being connected to a cam rod or bar 6 carrying cams 7A, 7B and 7C which act upon projections of microswitches 8A and 8B.

The cylinders and/ or plungers are provided with packing washers 9, but there is a tendency for these washers to let oil leak past the plungers until suflicient pressure has built up in them to cause the edges of the washers to be forced against the sides of the cylinders or plungers thus preventing leakage.

The apparatus however is provided with means for maintaining a suitable pressure, e.g., about 50 lbs. per square inch in the cylinders so that the washers are always held with their edges against the sides of the cylinders or plungers.

The pressure maintaining means comprises air compressing means (not shown) connected to a compressed air inlet 10, a pipe 11 leading from the inlet to one side of a plunger 12 in a third cylinder 13 and an oil-filled pipe 14 leading from the other side of the plunger 12 to the pipe 3 connecting the master cylinder 1 to the slave cylinder 4. In order that the maintained minimum pressure shall not adversely affect the movement of the cam rod or bar 6 a further pipe 15 is provided which leads from the air inlet to one side of a plunger 16 in a cylinder 17 the other side of the plunger 16 being connected to the end of the cam rod or bar 6 which is remote from the slave cylinder 4. Thus the pressure of about 50 lbs. per square inch acts on both ends of the cam rod 6.

The cam rod 6 is a rod having two bars 6A, 6B, T-shaped in cross-section. Each barcarries a cam or set of cams (7A, 7B, 7C) projecting out either side of the rod. The microswitches carry projections (80, 8D) upon which the cams act and the projections and cams are formed and arranged so that the switches may be actuated in one direction by projections 8C as on switches 8A or both directions by projections 8D as on switches 8B of movement of the rod 6, and may be held on or oil? for a period by cams 7B or 7C or may be actuated and then released immediately by cams 7A. The cams are adjustably mounted so that different sequences of operation of the switches may be set.

On the oil-filled side of the third cylinder 13 there are provided topping-up means which are connected to the pipe leading from the third cylinder and which comprise a non-return valve 18 and an oil top-up cup 19. A nonreturn valve 20 is also provided in the pipe 14 leading to the pipe 3 connecting the master and slave cylinders. At or near the master cylinder 1 there is provided a bleed outlet 21.

The apparatus operates as follows:

The plunger 2 of the master cylinder 1 is depressed by the ram of the hydraulic press. Oil is forced along the pipe 3 to the slave cylinder 4. The non-return valve 20 in the pipe 14 leading to the pipe 3 connecting the master and slave cylinders prevents oil flow to the third cylinder 13. The slave cylinder 4 moves the cam bar 6 and the cams 7A, 7B, 70 contact the projections of the switches 8A, 83 to operate the switches. The third or pressurising and replenishing cylinder 13 maintains the oil in the circuit under pressure, thus pressurising the oil seals or washers and making up any slight loss through seepage. To refill the third cylinder 13 the cup 19 of the topping-up means is filled with oil, the air inlet 10 is closed and the plunger 12 in the third cylinder 13 is pulled back, thus drawing oil from the cup 19 into the third cylinder 13. The non-return valve 18 in the pipe leading to the pipe connecting the master and slave cylinders obviates the necessity for the lid of the cup to be made air tight.

In known apparatus the microswitches are operated by the ram or device attached to the ram of a hydraulic press. This has the disadvantage, however, that it may be necessary to climb onto the press in order to adjust and set the switches. By the use of the present invention all microswitches can be situated where most convenient for setting and adjusting.

In the modification shown in FIGURE 2 the constant supply of fluid pressure to the fluid system comprising the cylinders 1, 4 and the pipe 3 connecting them is such that a supply of fluid (oil) under pressure is provided to the system during the return stroke of the press ram and is cut off during the power stroke of the press ram. The parts 11, 12, 13, 18, 19 of FIGURE 1 are replaced by a pump or other device (not shown) for supplying oil under pressure through a reducing valve 30 to an on-olf valve 31. The valve 31 is connected to the pipe 14. The valve 31 is solenoid operated and is of the type which is urged to the open position by a spring and is closed by energising the solenoid coil, this being effected by a battery 32 and microswitch 33. The switch 33 is actuated by a part 35 carried by the press ram. When the press ram starts to move on its downward stroke it actuates the microswitch to close the valve and shut oil? oil pressure to the pipe 14. On the return stroke the microswitch is reversed to de-energise the solenoid whereupon the valve opens and fluid under pressure is again admitted to the connecting pipe 3 and cylinders 1, 4 to maintain the system 3, 1, 4 full of oil under pressure.

What is claimed-is:

1. In a hydraulic press having a ram the provision of control apparatus comprising a first piston connected to the ram, a master cylinder for said piston, a slave cylinder, a conduit connecting said master and slave cylinders, a second piston in said slave cylinder, a plurality of switches for effecting various operations of the hydraulic press and a cam bar connected to the second piston so that when the ram moves it moves the first piston in the master cylinder which forces oil through the conduit to the slave cylinder whereby the second piston is moved to move the cam rod which operates the switches.

2. A hydraulic ram as claimed in claim 1, wherein means are provided for maintaining a minimum fluid pressure on said first and second pistons and for ensuring that the cam bar does not operate by means of the minimum pressure.

3. A hydraulic ram as claimed in claim 2, wherein said means includes means to supply fluid constantly under pressure to the conduit which connects the master and slave cylinders together.

4. A hydraulic ram as claimed in claim 2, wherein said means comprises air compressing means connected to a compressed air inlet, a pipe leading from the inlet to one side of a piston in a third piston and cylinder means, an oil-fil1ed pipe leading from the other side of the piston to the master and slave cylinders, and a further pipe leading from the air inlet to one side of a piston in a cylinder, the other side of this piston being connected to the end of the cam bar remote from the second piston.

5. A hydraulic ram as claimed in claim 1, wherein the cam bar comprises two rods T-shaped in cross-section, each rod carrying a set of cams projecting out either side of the bar which cams are adapted to act on projections carried by microswitches.

6. A hydraulic ram as claimed in claim 5, wherein the cams are adjustable along the cam bar.

7. A hydraulic press as claimed in claim 3, wherein said means includes a solenoid operated valve and a switch for controlling electric current supply to the solenoid, said switch being actuated by a part carried by the press ram.

References Cited Downs et al -545 MARTIN P. SCHWADRON, Primary Examiner.

ROBERT R. BUNEVICH, Examiner. 

